My sponsor she going to file i-864 and she self employed but she didnt have her W-2 AND FORM 1099?

Perhaps she has Schedules A, C etc, to establish what her income is.

How to find out whether or not a person is under a 10 year ban from the USCIS?

They will tell the person at the embassy, or you can determine the facts in their case and apply the law and determine if they are subject. There...

Legal name change evidence issue

You could try to explain that to them.

Yes, you can. Yes, there is a possibility to get an RFE.

You may wish to send your wife's form in response to her RFE. Otherwise, you should try to speak with a CIS agent to avoid getting her case denied.

Do I have to submit the I-751 waiver as soon as I receive my divorce decree?

No, you do not have to do that, but you may do that.

1. What is the consulate referring to as the "post"? 2. How should I send my information?

Post means the embassy or consulate.

K1 visa fraud

There is no crime. She will not be able to stay in the U.S. since she did not marry the K1 petitioner.

Notice Period.

You may wish to speak with a labor attorney about this, it is not an immigration question.

Under employment info should I say I worked in the US? For DS-260

See a lawyer. Your unauthorized employment could result in the embassy finding unlawful presence, barring you from admission for 3 or 10 years.